Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2508.17989 · Physical Review Letters

Incompressible Quantum Hall Liquid on the Four-Dimensional Sphere

Junwen Zhao, Xue Meng, Wei Zhu, Congjun Wu

Published Feb 9, 2026• 1 citation
arXivHTMLPDF

Abstract

The quantum Hall effect (QHE) is a cornerstone of topological physics, inspiring extensive explorations of its high-dimensional generalizations such as experimental realizations in synthetic systems including cold atoms, photonic lattices, and metamaterials. However, the many-body effect in the higher dimensional QHE system remains poorly understood. We explore this problem by formulating the microscopic wave functions on a four-dimensional sphere inspired by Laughlin's seminal work. Employing a generalized pseudopotential framework, we derive an exact microscopic Hamiltonian consisting of two-body projection operators that annihilate the microscopic wave functions. Diagonalizations on finite system sizes show that the quasihole states remain zero energy while the quasiparticle states exhibit a finite gap, in consistency with an incompressible state. Furthermore, the pair distribution is calculated to substantiate the liquidlike nature of the wave function. Our Letter provides a preliminary understanding to the fractional quantum Hall states in high dimensions.

DOI
10.1103/qygs-j2ys

Related papers

Toward a New Theory of the Fractional Quantum Hall Effect

Sergey A. Mikhailov

The fractional quantum Hall effect was experimentally discovered in 1982. It was observed that the Hall conductivity σyx of a two-dimensional electron system is quantized, σyx=e2/3h, in the vicinity of the Landau level filling factor ν=1/3. In 1983, Laughlin proposed a trial many-body wave function, which he claimed described a “new state of matter”—a homogeneous incompressible liquid with fractionally charged quasiparticles. Here, I develop an exact diagonalization theory that allows one to calculate the energy and other physical properties of the ground and excited states of a system of N two-dimensional Coulomb interacting electrons in a strong magnetic field. I analyze the energies, electron densities, and other physical properties of the systems with N≤7 electrons continuously as a function of magnetic field in the range 1/4≲ν<1. The results show that both the ground and excited states of the system resemble a sliding Wigner crystal whose parameters are influenced by the magnetic field. Energy gaps in the many-particle spectra appear and disappear as the magnetic field changes. I also calculate the physical properties of the ν=1/3 Laughlin state for N≤8 and compare the results with the exact ones. This comparison, as well as an analysis of some other statements published in the literature, show that the Laughlin state and its fractionally charged excitations do not describe the physical reality, neither at small N nor in the thermodynamic limit. The results obtained shed new light on the nature of the ground and excited states in the fractional quantum Hall effect.

arXiv:2206.05152•Nanomaterials•Jan 31, 2024•1 citation

Fractional quantum Hall states on CP2 space

Jie Wang, Semyon Klevtsov, Michael R. Douglas

We study four-dimensional fractional quantum Hall states on ${\mathbb{CP}}^{2}$ geometry from microscopic approaches. While in 2d the standard Laughlin wave function, given by a power of Vandermonde determinant, admits a product representation in terms of the Jastrow factor, this is no longer true in higher dimensions. In 4d, we can define two different types of Laughlin wave functions, the determinant-Laughlin and Jastrow-Laughlin states. We find that they are exactly annihilated by, respectively, two-particle and three-particle short-ranged interacting Hamiltonians. We then mainly focus on the ground state, low-energy excitations, and the quasihole degeneracy of determinant-Laughlin state. The quasihole degeneracy exhibits an anomalous counting, indicating the existence of multiple forms of quasihole wave functions. We argue that these are captured by the mathematical framework of ``commutative algebra of $N\mathrm{points}$ in the plane.'' The microscopic wave functions and Hamiltonians studied in this work pave the way for a systematic study of a high-dimensional topological phase of matter that is potentially realizable in cold atom and optical experiments.

arXiv:2109.11522•Physical Review Research•Apr 20, 2023•1 citation

Fractional Quantum Hall Effect from Frustration-Free Hamiltonians

Bo Yang

We show that there is an emergent lattice description for the continuous fractional quantum Hall (FQH) systems, with a generalized set of few-body coherent states. In particular, model Hamiltonians of the FQH effect (FQHE) are equivalent to the real-space von Neumann lattice of local projection operators imposed on a continuous system in the thermodynamic limit. It can be analytically derived that tuning local one-body potentials in such lattices amounts to the tuning of individual two- or few-body pseudopotentials. For some cases, we can realize pure few-body pseudopotentials important for stabilizing exotic non-Abelian topological phases. Thus, this new approach can potentially lead to the experimental realization of coveted non-Abelian quantum fluids including the Moore-Read state and the Fibonacci state. The reformulation of the FQHE as a sum of local projections opens up new paths for rigorously proving the incompressibility of microscopic Hamiltonians in the thermodynamic limit.

arXiv:1911.04566•Physical Review Letters•Oct 19, 2020•8 citations

Generalized Model Fractional Quantum Hall States on Lattices

Guangyue Ji, Jie Wang

Model wavefunctions are essential for studying fractional quantum Hall (FQH) phases. They reveal the intricate connections between model FQH states, conformal field theory, Jack polynomials, and pseudopotential Hamiltonians. However, most model wavefunctions studied so far are in the continuum. In this work, we construct model wavefunctions and the corresponding exact parent Hamiltonians for the entire $Z_k$ Read--Rezayi series on a lattice. Our model wavefunctions obey a generalized clustering rule implemented on the lattice, which we find is encoded in the Macdonald polynomials providing a unified algebraic description of our lattice-specific model states. This ensures that the model states are exact zero-energy ground states of local density interactions and exhibit an infinitely large gap in the particle entanglement spectrum. Numerical studies of the Laughlin and Moore--Read series find the expected zero-mode and one-flux quasihole counting and positive energy gaps at the system sizes studied, and the available finite-size scaling suggests nonzero thermodynamic gaps. Tuning the model interaction range can drive a phase transition out of the FQH phase. Our work not only advances the theoretical understanding of the underlying mathematical structure of lattice model FQH states but also is potentially useful for designing exotic many-body phases in engineered quantum platforms.

arXiv:2605.13978•May 13, 2026•0 citations

Gaffnian and Haffnian: Physical relevance of nonunitary conformal field theory for the incompressible fractional quantum Hall effect

Bo Yang

We motivate a close look on the usefulness of the Gaffnian and Haffnian quasihole manifold (null spaces of the respective model Hamiltonians) for well-known gapped fractional quantum Hall phases. The conformal invariance of these subspaces is derived explicitly from microscopic many-body states. The resultant conformal field theory (CFT) description leads to an intriguing emergent primary field with $h=2,\phantom{\rule{0.28em}{0ex}}c=0$, and we argue the quasihole manifolds are quantum mechanically well defined and well behaved. Focusing on the incompressible phases at $\ensuremath{\nu}=\frac{1}{3}$ and $\frac{2}{5}$, we show the low-lying excitations of the Laughlin phase are quantum fluids of Gaffnian and Haffnian quasiholes, and give a microscopic argument showing that the Haffnian model Hamiltonian is gapless against Laughlin quasielectrons. We discuss the thermal Hall conductance and shot-noise measurements at $\ensuremath{\nu}=\frac{2}{5}$, and argue that the experimental observations can be understood from the dynamics within the Gaffnian quasihole manifold. A number of detailed predictions on these experimental measurements are proposed, and we discuss their relationships to the conventional CFT arguments and the composite fermion descriptions.

arXiv:2010.13799•Physical review. B./Physical review. B•Mar 2, 2021•14 citations

Microscopic computations in the fractional quantum Hall effect

Stephanie Jane Huntington

The microscopic picture for fractional quantum Hall effect (FQHE) is difficult to work with analytically for a large number of electrons. Therefore to make predictions and attempt to describe experimental measurements on quantum Hall systems, effective theories are usually employed such as the chiral Luttinger liquid system. In this thesis the Monte Carlo method is used for Laughlin-type quantum Hall systems to compute microscopic observables. In particular such computations are carried out for the large system size expansion of the free energy. This work was motivated by some disagreement in the literature about the form of the free energy expansion and is still an ongoing project. Tunnelling in the FQHE is an interesting problem since the tunnelling operators are derived from an effective theory which has not yet been checked microscopically. To perform a test for the effective tunnelling Hamiltonian, microscopic calculations were performed numerically for charges tunnelling across the bulk states of a FQH device. To compute these matrix elements, two methods were found to overcome a phase problem encountered in the Monte Carlo simulations. The Monte Carlo results were compared to the matrix elements predicted by the effective tunnelling Hamiltonian and there was a good match between the data. Performing this comparison enabled the operator ordering in the effective tunnelling Hamiltonian to be deduced and the data also showed that the quasiparticle tunnelling processes were more relevant than the electron tunnelling processes for all system sizes, supporting the idea that when tunnelling is considered at a weak barrier, the electron tunnelling process can be neglected.

•May 11, 2015•0 citations
The quantum Hall effect (QHE) is a cornerstone of topological physics, inspiring extensive explorations of its high-dimensional generalizations such as experimental realizations in synthetic systems including cold atoms, photonic lattices, and metamaterials. However, the many-body effect in the higher dimensional QHE system remains poorly understood. We explore this problem by formulating the microscopic wave functions on a four-dimensional sphere inspired by Laughlin's seminal work. Employing a generalized pseudopotential framework, we derive an exact microscopic Hamiltonian consisting of two-body projection operators that annihilate the microscopic wave functions. Diagonalizations on finite system sizes show that the quasihole states remain zero energy while the quasiparticle states exhibit a finite gap, in consistency with an incompressible state. Furthermore, the pair distribution is calculated to substantiate the liquidlike nature of the wave function. Our Letter provides a preliminary understanding to the fractional quantum Hall states in high dimensions.
The fractional quantum Hall effect was experimentally discovered in 1982. It was observed that the Hall conductivity σyx of a two-dimensional electron system is quantized, σyx=e2/3h, in the vicinity of the Landau level filling factor ν=1/3. In 1983, Laughlin proposed a trial many-body wave function, which he claimed described a “new state of matter”—a homogeneous incompressible liquid with fractionally charged quasiparticles. Here, I develop an exact diagonalization theory that allows one to calculate the energy and other physical properties of the ground and excited states of a system of N two-dimensional Coulomb interacting electrons in a strong magnetic field. I analyze the energies, electron densities, and other physical properties of the systems with N≤7 electrons continuously as a function of magnetic field in the range 1/4≲ν<1. The results show that both the ground and excited states of the system resemble a sliding Wigner crystal whose parameters are influenced by the magnetic field. Energy gaps in the many-particle spectra appear and disappear as the magnetic field changes. I also calculate the physical properties of the ν=1/3 Laughlin state for N≤8 and compare the results with the exact ones. This comparison, as well as an analysis of some other statements published in the literature, show that the Laughlin state and its fractionally charged excitations do not describe the physical reality, neither at small N nor in the thermodynamic limit. The results obtained shed new light on the nature of the ground and excited states in the fractional quantum Hall effect.
We study four-dimensional fractional quantum Hall states on CP2{\mathbb{CP}}^{2}CP2 geometry from microscopic approaches. While in 2d the standard Laughlin wave function, given by a power of Vandermonde determinant, admits a product representation in terms of the Jastrow factor, this is no longer true in higher dimensions. In 4d, we can define two different types of Laughlin wave functions, the determinant-Laughlin and Jastrow-Laughlin states. We find that they are exactly annihilated by, respectively, two-particle and three-particle short-ranged interacting Hamiltonians. We then mainly focus on the ground state, low-energy excitations, and the quasihole degeneracy of determinant-Laughlin state. The quasihole degeneracy exhibits an anomalous counting, indicating the existence of multiple forms of quasihole wave functions. We argue that these are captured by the mathematical framework of ``commutative algebra of NpointsN\mathrm{points}Npoints in the plane.'' The microscopic wave functions and Hamiltonians studied in this work pave the way for a systematic study of a high-dimensional topological phase of matter that is potentially realizable in cold atom and optical experiments.
We show that there is an emergent lattice description for the continuous fractional quantum Hall (FQH) systems, with a generalized set of few-body coherent states. In particular, model Hamiltonians of the FQH effect (FQHE) are equivalent to the real-space von Neumann lattice of local projection operators imposed on a continuous system in the thermodynamic limit. It can be analytically derived that tuning local one-body potentials in such lattices amounts to the tuning of individual two- or few-body pseudopotentials. For some cases, we can realize pure few-body pseudopotentials important for stabilizing exotic non-Abelian topological phases. Thus, this new approach can potentially lead to the experimental realization of coveted non-Abelian quantum fluids including the Moore-Read state and the Fibonacci state. The reformulation of the FQHE as a sum of local projections opens up new paths for rigorously proving the incompressibility of microscopic Hamiltonians in the thermodynamic limit.
Model wavefunctions are essential for studying fractional quantum Hall (FQH) phases. They reveal the intricate connections between model FQH states, conformal field theory, Jack polynomials, and pseudopotential Hamiltonians. However, most model wavefunctions studied so far are in the continuum. In this work, we construct model wavefunctions and the corresponding exact parent Hamiltonians for the entire ZkZ_kZk​ Read--Rezayi series on a lattice. Our model wavefunctions obey a generalized clustering rule implemented on the lattice, which we find is encoded in the Macdonald polynomials providing a unified algebraic description of our lattice-specific model states. This ensures that the model states are exact zero-energy ground states of local density interactions and exhibit an infinitely large gap in the particle entanglement spectrum. Numerical studies of the Laughlin and Moore--Read series find the expected zero-mode and one-flux quasihole counting and positive energy gaps at the system sizes studied, and the available finite-size scaling suggests nonzero thermodynamic gaps. Tuning the model interaction range can drive a phase transition out of the FQH phase. Our work not only advances the theoretical understanding of the underlying mathematical structure of lattice model FQH states but also is potentially useful for designing exotic many-body phases in engineered quantum platforms.
We motivate a close look on the usefulness of the Gaffnian and Haffnian quasihole manifold (null spaces of the respective model Hamiltonians) for well-known gapped fractional quantum Hall phases. The conformal invariance of these subspaces is derived explicitly from microscopic many-body states. The resultant conformal field theory (CFT) description leads to an intriguing emergent primary field with h=2,c=0h=2,\phantom{\rule{0.28em}{0ex}}c=0h=2,c=0, and we argue the quasihole manifolds are quantum mechanically well defined and well behaved. Focusing on the incompressible phases at $\ensuremath{\nu}=\frac{1}{3}$ and 25\frac{2}{5}52​, we show the low-lying excitations of the Laughlin phase are quantum fluids of Gaffnian and Haffnian quasiholes, and give a microscopic argument showing that the Haffnian model Hamiltonian is gapless against Laughlin quasielectrons. We discuss the thermal Hall conductance and shot-noise measurements at $\ensuremath{\nu}=\frac{2}{5}$, and argue that the experimental observations can be understood from the dynamics within the Gaffnian quasihole manifold. A number of detailed predictions on these experimental measurements are proposed, and we discuss their relationships to the conventional CFT arguments and the composite fermion descriptions.
The microscopic picture for fractional quantum Hall effect (FQHE) is difficult to work with analytically for a large number of electrons. Therefore to make predictions and attempt to describe experimental measurements on quantum Hall systems, effective theories are usually employed such as the chiral Luttinger liquid system. In this thesis the Monte Carlo method is used for Laughlin-type quantum Hall systems to compute microscopic observables. In particular such computations are carried out for the large system size expansion of the free energy. This work was motivated by some disagreement in the literature about the form of the free energy expansion and is still an ongoing project. Tunnelling in the FQHE is an interesting problem since the tunnelling operators are derived from an effective theory which has not yet been checked microscopically. To perform a test for the effective tunnelling Hamiltonian, microscopic calculations were performed numerically for charges tunnelling across the bulk states of a FQH device. To compute these matrix elements, two methods were found to overcome a phase problem encountered in the Monte Carlo simulations. The Monte Carlo results were compared to the matrix elements predicted by the effective tunnelling Hamiltonian and there was a good match between the data. Performing this comparison enabled the operator ordering in the effective tunnelling Hamiltonian to be deduced and the data also showed that the quasiparticle tunnelling processes were more relevant than the electron tunnelling processes for all system sizes, supporting the idea that when tunnelling is considered at a weak barrier, the electron tunnelling process can be neglected.